A stroke detection device includes a cell phone having a sensor adapted to sense a characteristic of the user of the cell phone. An app executed by the cell phone passively monitors the characteristic to determine if the user has experienced a stroke. The app requests that the user take one or more tests using the cell phone if the presence of a stroke is possible. The tests include the user speaking a specific phrase into the cell phone that is compared to a previously recorded sound sample of the user； the user taking a picture of himself or herself with the cell phone that the app compares to a previous picture of the user； and the user attempting to hold his or her arm out straight while holding the cell phone wherein accelerometers in the phone measure the steadiness of his or her arm.
